Particle physics & cancer therapy – what’s the link?

Protons are at the centre of everything, lying within every atom that makes up the world around us. Together with neutrons and electrons, they are part of everything we see and touch, constituting (almost) all of the accounted for mass in the universe. Since their discovery by Ernest Rutherford at the University of Manchester in the early 1900s, these particles have both intrigued and puzzled physicists across the globe.

Despite our still-developing understanding of their complex behaviour and structure, subatomic particles (of which protons are one) have become increasingly important to our everyday lives, from security scanning to developing microchips. But what is the link between protons and our health, how did we get there, and what’s next?

Starting out

Rutherford’s initial discovery led to a whole new field of research; nuclear physics. Scientists were keen to learn more about atomic structure, how it is formed and how these particles interact with each other. John Cockcroft and Ernest Walton were no exception, setting to work quickly on developing the world’s first particle accelerator. Their aim was to propel particles at increasingly high speeds, and then collide them with either a target or another travelling particle. This collision can create new matter which can then be detected and analysed to inform our knowledge of the universe.

Whilst scientists across the world were learning more and more each year about the make-up of our universe thanks to particle acceleration, the increasing ability to accelerate protons got Robert Wilson, then Harvard scientist and later founder of Fermilab, thinking about wider applications of the technology.

Protons in healthcare

Since the discovery of x-rays in the early 1900s, radiation therapy, alongside chemotherapy and surgery, has been a common form of treatment for cancers. Through a process known as ionisation, x-ray photons can destroy genes within a cell, resulting in cell death and the shrinking of tumours. For a long time x-rays were the only option for radiation therapy as, unlike other waves or particles, they could naturally travel through human tissue. However, Wilson saw a chance to investigate the use of protons for therapeutic purposes too, using particle acceleration to give protons the additional energy needed to penetrate human tissue, as x-rays could already do.

Protons represent an interesting method for treating cancer due to their unique energy profile. While x-ray photons travel straight through the body, depositing radiation as they move through, protons deliver the majority of their radiation dose at a single peak. This phenomenon is known as the Bragg Peak (see picture below). On first entry into the body, the high speed of the protons from the particle accelerator means little of the radiation dose is deposited within the tissues. As the protons gradually slow down, the dose delivered to the cells increases, quickly rising to a peak as they stop. The depth at which this energy peak occurs can be controlled by adjusting the amount of energy delivered to the protons through the particle accelerator – greater acceleration = deeper peak of dose. Importantly, this difference in behaviour between protons and x-rays means that proton beam therapy can be a more precise form of radiation therapy, delivering the majority of the radiation dose direct to the tumour site and reducing damage to surrounding healthy cells, ultimately reducing side effects for patients.

Unfortunately, despite being one of the most advanced and effective forms of radiation therapy, access to proton beam therapy is limited. Treatment centres are larger and more expensive to build than conventional radiotherapy centres, due to the size and complexity of the accelerators, as well as the shielding required to contain the radiation. This reflects in the small number of centres operating globally (currently around 70), and consequently the limited numbers of patients that can access, or afford the treatment.

Growth in the North West

In response to these challenges, companies and organisations are increasingly looking at innovative ways to enable broader access to proton beam therapy, and the North West is uniquely placed to support. A long history of science and innovation has placed the region at the forefront of expertise in particle acceleration, from Rutherford’s initial discovery of protons to the growth of centres such as the Science and Technology Facilities Council’s (STFC) Daresbury Laboratory, which was born out of decades of advanced accelerator R&D. This includes the operation of the SRS synchrotron which supported research towards three Nobel prizes, as well as the famous ‘Daresbury Tower’, a 71m high tower which contained a vertical accelerator for nuclear physics research. Within healthcare, The Clatterbridge Cancer Centre on the Wirral was also the first hospital-based proton treatment centre in the world and has so far treated almost 3000 patients with ocular (eye) melanomas.

The impact of this strong heritage is apparent in the burgeoning work across industry and healthcare more recently. In 2018, STFC signed a major new agreement with Advanced Oncotherapy plc to build an assembly and testing centre at Daresbury Laboratory for a new generation of proton therapy, designed to improve performance and reduce costs. Advanced Oncotherapy plc had acquired ADAM, a spin-out from CERN (the home of the Large Hadron Collider), which had begun the development of a commercial proton therapy system based on CERN research. For the next stage in their journey, the company chose to locate at Daresbury Laboratory’s iconic tower on the Sci-Tech Daresbury campus. This was in order to take advantage of the pre-existing infrastructure, as well as the extensive on-site experience in developing accelerator systems; helping them to reduce risk, and save time and money. Once building and testing have been completed Advanced Oncotherapy plc’s first ‘LIGHT system’ will be small enough to be installed within the space of two terraced houses in Harley Street, Central London, and is expected to be the world’s first commercially available linear proton accelerator for proton beam therapy.

Other companies, such as Rutherford Health, are also driving the development of proton beam therapy in the North West, with the construction of the new Rutherford Cancer Centre in the Knowledge Quarter, Liverpool, which will eventually provide proton beam therapy services for patients. Rutherford Health was the first to bring proton beam therapy to the UK at its centre in Newport, Wales, in 2018, and the Liverpool centre will be the first in the UK to use an MR Linac machine, which combines an MRI scanner and a linear accelerator to provide highly accurate radiotherapy treatment. IBA and Varian are also key industrial players in the sector providing leading technology to cancer centres across the region, nationally and internationally.

Progress has also been made in public healthcare settings, with the opening of the first NHS high-energy proton beam therapy centre in the UK at The Christie (Manchester) in 2018. In addition, the hospital has developed a dedicated proton beamline for research purposes, in collaboration with scientists at The Cockcroft Institute, also based at Sci-Tech Daresbury to help develop novel future proton treatment methods.

This unique combination of world-leading expertise in particle accelerators with leading academic and medical institutions, as well as a suite of innovative businesses, places the North West at the forefront of advanced medical accelerator research, development, evaluation and treatment. And, whilst understanding the links between subatomic particle research and our day-to-day lives can be difficult to comprehend, the development and evolution of proton beam therapy illustrates the undeniably important links between our fundamental understanding of science with opportunities for world-changing innovation.

There are a range of opportunities for businesses and/or researchers working in this field, here’s just a few:

• STFC Daresbury Laboratory’s accelerator facilities – For manufacturers of radiotherapy technology, STFC Daresbury Laboratory’s accelerator facilities, radiation test cells and team of scientists and engineers with decades of experience in designing, building and operating particle accelerators are available to support your R&D programme.​ Find out more.
• STFC CERN Business Incubation Centre – Small companies interested in utilising high-energy physics technologies in new ways can also apply for the STFC CERN Business Incubation Centre, which provides a package of funding, expertise, business support and access to unique IP. The next Expression of Interest closes on 31^st
• HealthTec Cluster – Sci-Tech Daresbury hosts the HealthTec Cluster North West, which connects capabilities across the region – find out about current activities and opportunities by signing up to the newsletter.
• STFC Cancer Diagnosis + Network – If you’re interested in helping to develop solutions for clinical challenges in the diagnosis of cancer, the STFC Cancer Diagnosis + Network brings together a multidisciplinary community of academics, clinical and industry members to collaborate on a range of themes. Find out more.

Sci-Tech Daresbury has a range of offices, laboratories and workshops to meet the needs of companies of all sizes and is the ideal home for science and technology companies looking to collaborate on-site with STFC.